Aerosol dispensers are well known in the art. Aerosol dispensers typically comprise an outer container which acts as a frame for the remaining components and as a pressure vessel for propellant and product contained therein. Outer containers made of metal are well known in the art. However, metal containers can be undesirable due to high cost and limited recyclability. Attempts to use plastic have occurred in the art. Relevant attempts in the art to employ plastic in aerosol dispensers are found in U.S. Pat. Nos. 2,863,699; 3,333,743; 9,296,550; 9,334,103 and 2009/0014679.
The outer containers are typically, but not necessarily, cylindrical. The outer container may comprise a closed end bottom adjoining the sidewalls and for resting on horizontal surfaces such as shelves, countertops, tables etc. The bottom of the outer container may comprise a re-entrant portion as shown in U.S. Pat. No. 3,403,804 or base cup as shown in U.S. Pat. No. 9,061,795. Sidewalls defining the shape of the outer container extend upwardly from the bottom to an open top.
The open top defines a neck for receiving additional components of the aerosol dispenser. The industry has generally settled upon a nominal neck diameter of 2.54 cm, for standardization of components among various manufacturers, although smaller diameters, such as 20 mm, are also used. Various neck shapes are shown in U.S. Pat. Nos. 6,019,252; 7,028,866; 7,279,207 and 7,303,087.
Typically a valve cup is inserted into the neck. The valve cup is sealed against the neck to prevent the escape of the propellant and loss of pressurization, such as described in U.S. Pat. Nos. 8,074,847; 8,096,327; 8,844,765 and 8,869,842. The valve cup holds the valve components which are movable in relationship to the balance of the aerosol dispenser. Suitable valves are shown in commonly assigned U.S. Pat. Nos. 8,511,522 and 9,132,955. When the valves are opened, product may be dispensed through a nozzle, etc. as described in commonly assigned U.S. Pat. No. 9,174,229.
A valve may be inserted into the valve cup for selective actuation by the user. The valve is typically normally closed, but may be opened to create a flow path for the product to ambient or a target surface. The valve may be compatible with local recycling standards. Suitable valves are disclosed in commonly assigned U.S. Pat. Nos. 8,511,522 and 9,132,955.
If a valve is to be assembled into an aerosol, typically the valve cup is crimped onto the neck of the aerosol container. But this operation is expensive and is difficult to perform with a plastic valve cup. A separate interlock may be used to attach a valve to a valve cup, particularly a plastic valve and plastic valve cup are used. Suitable interlocks include bayonet fittings and threads as disclosed in commonly assigned P&G application, Case 14458, Ser. No. 15/235,237, filed Aug. 12, 2016. A pressure vessel with a threaded bore is proposed in U.S. Pat. No. 8,505,762.
A bag may be used to contain product for selective dispensing by a user. Dispensing of product from the bag occurs in response to the user actuating the valve. The bag separates product within the bag from propellant disposed between the bag and container. This bag limits or even prevents intermixing of the contents of the bag and the components outside of the bag. Thus, product may be contained in the bag. Propellant may be disposed between the outside of the bag and the inside of the outer container. Upon actuation of the valve, a flow path out of the bag is created. This embodiment is commonly called a bag in can and may be used, for example, in dispensing shaving cream gels. Alternatively, a bag may be directly joined to the valve housing, in a configuration commonly called a bag on valve. A suitable bag configuration is disclosed in commonly assigned application, P&G Case 14458, Ser. No. 15/235,227, filed Aug. 12, 2016 which teaches attaching a bag to a valve cup.
If a bag configuration is desired, propellant may be disposed between the bag and outer container, as disclosed in commonly assigned U.S. Pat. Nos. 8,631,632 and 8,869,842. Afterwards, product fill may occur in a separate, remote, operation, optionally carried out in another location, which may be in the same country or in a different country. Such a manufacturing process can conserve costs in production, shipment and/or storage.
An aerosol container having a bag therein may be made from a dual layer preform, having plural layers disposed one inside the other. Relevant attempts include U.S. Pat. Nos. 3,450,254; 4,330,066; 6,254,820; RE 30093 E; and publications WO 9,108,099 and US 2011/0248035 A1. But each of these attempts requires a separate operation to attach the bag to the relevant component. Each attachment step takes time in manufacturing and creates the opportunity for leakage if not correctly performed. Improvements in dual layer preforms are found in commonly assigned application P&G Case 14461, application Ser. No. 15/235,279, filed Aug. 12, 2016.
Alternatively, a dip tub may be used if intermixing of the product and propellant is desired. When the user actuates the valve, the product and propellant are dispensed together through the dip tube. One configuration is shown in commonly assigned U.S. Pat. No. 6,039,222. This embodiment may utilize a dip tube. The dip tube takes the product and propellant mixture from the bottom of the outer container. Or a piston may be used to expel product, if it is particularly viscous, as described in commonly assigned US publication 2016/0368633.
But aerosol dispensers have typically been used to dispense products which can be used independent of the product temperature. For example, aerosol dispensers are commonly used to dispense cleaning products, insecticide, air fresheners, shaving cream, etc. These products are ubiquitously dispensed at the temperature ambient to the aerosol dispenser, typically room temperature.
But room temperature may not be optimum for all products. Some products may be more optimally used in a warmed or heated condition, the terms being used interchangeably. For example, certain foods are more palatable when served warm. Air freshener may disperse better when warmed. Shaving cream may be perceived to be more comfortable when warmed. Commonly assigned applications, P&G Case 14735, application Ser. No. 15/444,354 and P&G Case 14736, Ser. No. 15/444,356 disclose heating of aerosol dispensers in a microwave oven.
Overpressurization, and rupture may occur, for example, during microwave heating if a microwavable aerosol is left unattended or during manufacture if excessive propellant charge occurs. U.S. Pat. No. 9,394,098 teaches an adapter collar which can purportedly function as a safety shield in the event of overpressurization and rupture. But this attempt adds complexity and additional leakage pathways. And this adapter collar may be ineffective in the case of rupture. U.S. Pat. Nos. 3,074,602; 3,292,826; 3,372,827 and 3,815,534 teaches score lines and a pressure relief valve for an aerosol can. But these attempts in the art rely upon precise tolerances and precision manufacture to properly work relieve pressure in the event of overpressurization. Such tolerances may be difficult to maintain in high speed production.
Accordingly, it is an object of this invention to provide an aerosol dispenser which minimizes occurrences of rupture in the event of overpressurization, through integral venting.